Crashlytics in Android Kotlin - Mini App: Build & Ship

Build: Crashlytics Demo Screen

This screen demonstrates how to integrate Firebase Crashlytics to catch and report app crashes in an Android app using Kotlin.

Target UI

-------------------------
| Crashlytics Demo      |
|-----------------------|
| [Crash App Button]    |
|                       |
| Tap the button to     |
| cause a crash and     |
| send a report to      |
| Firebase Crashlytics. |
-------------------------

Add Firebase Crashlytics dependency and initialize it.

Create a button labeled 'Crash App Button'.

When the button is tapped, force a crash by throwing a RuntimeException.

Ensure the crash is reported to Firebase Crashlytics.

Starter Code

Android Kotlin

package com.example.crashlyticsdemo

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import android.widget.Button

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val crashButton: Button = findViewById(R.id.crashButton)
        // TODO: Set click listener to cause a crash
    }
}

Task 1

Solution

Android Kotlin

package com.example.crashlyticsdemo

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import android.widget.Button

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val crashButton: Button = findViewById(R.id.crashButton)
        crashButton.setOnClickListener {
            throw RuntimeException("Test Crash") // Force a crash
        }
    }
}

This code sets a click listener on the button labeled 'Crash App Button'. When tapped, it throws a RuntimeException which crashes the app. Firebase Crashlytics automatically catches this crash and sends a report to your Firebase console. Make sure Firebase Crashlytics is properly added and initialized in your project for this to work.

Final Result

Completed Screen

-------------------------
| Crashlytics Demo      |
|-----------------------|
| [Crash App Button]    |
|                       |
| Tap the button to     |
| cause a crash and     |
| send a report to      |
| Firebase Crashlytics. |
-------------------------

User taps 'Crash App Button'.

App immediately crashes with RuntimeException.

Crashlytics captures the crash and sends report to Firebase.

Stretch Goal

Add a log message to Crashlytics before crashing to provide extra context.

💡 Hint

Use FirebaseCrashlytics.getInstance().log("Your message") before throwing the exception.

Practice

1. What is the main purpose of Crashlytics in an Android app?

easy

A. To automatically track and report app crashes

B. To improve app UI design

C. To manage app navigation

D. To optimize app performance speed

Solution

1. Step 1: Understand Crashlytics functionality

   Crashlytics is a tool designed to detect and report app crashes automatically.

2. Step 2: Compare options with Crashlytics purpose

   Only To automatically track and report app crashes matches the core function of Crashlytics, which is crash tracking and reporting.

3. Final Answer:

   To automatically track and report app crashes -> Option A

4. Quick Check:

   Crashlytics = crash tracking [OK]

Hint: Crashlytics = crash reports automatically [OK]

Common Mistakes:

• Confusing Crashlytics with UI or navigation tools
• Thinking Crashlytics improves app speed
• Assuming Crashlytics manages app content

2. Which of the following is the correct way to add Crashlytics dependency in your app's build.gradle file?

easy

A. apply plugin: 'com.google.firebase.crashlytics'

B. compile 'com.google.firebase:firebase-crashlytics:18.3.7'

C. implementation 'com.google.firebase:firebase-analytics:18.3.7'

D. implementation 'com.google.firebase:firebase-crashlytics:18.3.7'

Solution

1. Step 1: Identify correct dependency syntax

   Modern Gradle uses 'implementation' to add dependencies, not 'compile' which is deprecated.

2. Step 2: Match Crashlytics dependency artifact

   The correct artifact for Crashlytics is 'firebase-crashlytics', not 'firebase-analytics'.

3. Final Answer:

   implementation 'com.google.firebase:firebase-crashlytics:18.3.7' -> Option D

4. Quick Check:

   Use implementation + firebase-crashlytics [OK]

Hint: Use 'implementation' with firebase-crashlytics artifact [OK]

Common Mistakes:

• Using deprecated 'compile' keyword
• Confusing Crashlytics with Analytics dependency
• Using plugin apply instead of dependency line

3. Given this Kotlin code snippet, what will Crashlytics record when the app crashes?

try {
  val result = 10 / 0
} catch (e: Exception) {
  Firebase.crashlytics.recordException(e)
}

medium

A. Crashlytics records the division by zero exception

B. No crash recorded because exception is caught

C. App will crash without any report

D. Crashlytics records a null pointer exception

Solution

1. Step 1: Analyze exception handling

   The division by zero throws an ArithmeticException, which is caught in the catch block.

2. Step 2: Check Crashlytics exception recording

   The caught exception is passed to Firebase.crashlytics.recordException(e), so Crashlytics logs it even without app crash.

3. Final Answer:

   Crashlytics records the division by zero exception -> Option A

4. Quick Check:

   recordException logs caught exceptions [OK]

Hint: recordException logs caught errors even if app doesn't crash [OK]

Common Mistakes:

• Thinking caught exceptions are ignored by Crashlytics
• Assuming app crashes without report
• Confusing exception types

4. You added Crashlytics to your app but no crash reports appear in the Firebase console. What is a common mistake causing this?

medium

A. Adding Crashlytics dependency in the wrong module

B. Using the wrong package name in build.gradle

C. Not initializing Firebase in the Application class

D. Calling recordException outside a try-catch block

Solution

1. Step 1: Check Firebase initialization

   Firebase must be initialized early, usually in the Application class, for Crashlytics to work.

2. Step 2: Evaluate other options

   Wrong package name or dependency module can cause issues but the most common is missing Firebase initialization.

3. Final Answer:

   Not initializing Firebase in the Application class -> Option C

4. Quick Check:

   Initialize Firebase early for Crashlytics [OK]

Hint: Always initialize Firebase in Application class [OK]

Common Mistakes:

• Forgetting FirebaseApp.initializeApp(context)
• Misplacing dependencies in modules
• Assuming recordException needs try-catch

5. You want to log a custom message and a user ID to Crashlytics before a crash happens. Which code snippet correctly does this?

hard

A. Firebase.crashlytics.log("User clicked the crash button")
throw RuntimeException("Test crash")
Firebase.crashlytics.setCustomKey("userId", "12345")

B. Firebase.crashlytics.setCustomKey("userId", "12345")
Firebase.crashlytics.log("User clicked the crash button")
throw RuntimeException("Test crash")

C. throw RuntimeException("Test crash")
Firebase.crashlytics.setCustomKey("userId", "12345")

D. Firebase.crashlytics.recordException(RuntimeException("Test crash"))
Firebase.crashlytics.setCustomKey("userId", "12345")

Solution

1. Step 1: Understand Crashlytics logging order

   Custom keys and logs must be set before the crash to be included in the report.

2. Step 2: Check code snippet order

   Firebase.crashlytics.setCustomKey("userId", "12345") Firebase.crashlytics.log("User clicked the crash button") throw RuntimeException("Test crash") sets the user ID and logs the message before throwing the crash, so data is captured correctly.

3. Final Answer:

   Set custom key and log before crash throw -> Option B

4. Quick Check:

   Set keys and logs before crash [OK]

Hint: Set keys/logs before crash throw to capture data [OK]

Common Mistakes:

• Setting keys after crash throw (too late)
• Using recordException instead of throwing crash
• Not logging custom messages